. Electric railway journal . Holder Mechanism forArmature-Testing Outfit tor. This adjustment is obtained by means of two slotsin the board through which the terminals are connected tothe brush holders. The illustrations also show a shelfabove the armature stand which is used for trying outand adjusting circuit-breakers. For this purpose the con-trollers and resistances are used to increase the currentuntil the circuit-breaker blows, the current being indicatedby the ammeter. Circuit-breakers used on four-motorequipments are set to blow at 325 amp, and those on two- acts as a secondary and a c
. Electric railway journal . Holder Mechanism forArmature-Testing Outfit tor. This adjustment is obtained by means of two slotsin the board through which the terminals are connected tothe brush holders. The illustrations also show a shelfabove the armature stand which is used for trying outand adjusting circuit-breakers. For this purpose the con-trollers and resistances are used to increase the currentuntil the circuit-breaker blows, the current being indicatedby the ammeter. Circuit-breakers used on four-motorequipments are set to blow at 325 amp, and those on two- acts as a secondary and a coil made up of eighty-one turnsof No. 5 D. C. C. wire acts as a primary. The primary coilreceives current from a small cio-volt, 35-cyde generator,which is driven directly from the main shaft. This coilalso has a 40-amp circuit-breaker, an ammeter and a 90-amp double-pole, single-throw switch in series. First thereading of the ammeter is noted when the switches areclosed and without a field coil in position for testing, this. B. R. T. Electrical Shops—Armature-Testing Outfit Show-ing Also Bracket for Circuit-Breaker reading corresponding to the primary current of the trans-former when the secondary is open-circuited; or this will bethe reading of the ammeter when the field coil under test isin good condition and without short-circuits. A readinghigher than this normal reading indicates that the field coilhas a short-circuit, the reading varying in accordance withthe number of turns thus short-circuited. If the currentis maintained for a while, the point of short-circuit willbe indicated by the additional heating of that portion of 486 ELECTRIC RAILWAY JOURNAL [Vol. XLI, No. ii. the coil. In testing for open circuits one terminal of thecoil is grounded and a light circuit is put on the otherterminal. The burning of the lamps, of course, will showthe absence of open circuits. The construction of the field-testing outfit consists ofthe parts shown in an accompanying drawing. The
Size: 1557px × 1605px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, bookidelectricrailway411913newy
